HUMAN remains unearthed on a Vatican-owned property in Rome may hold the key to solving the mystery of an Italian teen girl who vanished 35 years ago.

The New York Post reports that bone fragments were discovered during construction work at the Vatican’s embassy to Italy in the upscale neighbourhood of Parioli, the Vatican said late Tuesday.

While experts are still working to determine the age, gender and date of death of the remains, detectives will be looking in particular at whether they are a DNA match for Emanuela Orlandi — the daughter of a Holy See employee at the centre of one of Italy’s darkest mysteries.

The 15-year-old was last seen June 22, 1983, leaving her music lesson in Rome. Her father was an employee of the Institute for the Works of Religion, commonly known as the Vatican Bank.

Over the years, theories have linked her disappearance to everything from a plot to kill St. John Paul II to the financial scandal of the Vatican Bank and to Rome’s criminal underworld.

The last major twist happened in 2012 when police exhumed the body of a reputed mobster in the hopes of finding Orlandi’s remains buried in the same crypt — but the search turned up no link.

Orlandi’s brother Pietro has been leading a decades-long campaign to find out what happened and has even accused the Vatican of complicity in the case, The Guardian reported.

The Vatican has repeatedly said it has co-operated fully with police investigating the case.

Recently, a leading Italian journalist caused a stir when he published a document stolen from a locked Vatican cabinet that suggested the Holy See was involved in Orlandi’s disappearance. The document seemed to be written by a cardinal and listed supposed expenses for Orlandi’s upkeep after she vanished.

The Vatican said the document was a fake but never explained what it was doing in one of their cabinets.